Artificial limb



Sept. 25, 1928.

K. NEUMANN ARTIFICIAL LIMB Filed Oct. 27, 1926 I N V EN TOR. AARL Mmmvgrill, E2

A TI'ORNEY.

Patented Sept. 25, 1928.

UNI-TED GFFI'CE;

KARL NEUMANN, 0F MILWAUKEE; WISCONSIN.

ARTIFICIAL LIMB;

Application fired October 27, 1926; serial No. 144,441).

This" invention rel'at'es'to artificial limb-s. In artificial limb's'heretofore designed the thigh and shank portions are ordinarily pivotally' conneetecl'to swingabouta' definite axis which liears' a fixedrelation to Both portions n n angular'positions thereof; In fact the knee joint ordinarily ineliides a. pivot pin fixed to intersectthe' l'ongitiidi'nalfaxisof both portions; Such a disposition'of the pivot 18 objectionable in that the leg tendsto'buckle' under the weight of the wearer when standing in erect positiont Attempts to overcome this objeetion by arranging the pivot iirthe rearof the axes of these portions have not proven satisfactorybecause this'resultsin an extremely unnatural knee action: A rear- Wardly positioned pivot'o'ause's'an unnatural bulgingofthe'front'portion oi the knee and an unnatural levation of the adjacent portion of'tlie thigh when the limb is'b'ent as in a sittingposture.

One object of the present invention is the provision'of' a kneejoint vvhich will closely simulate the action of anaturalknee and at the same time sustain the weightof the'vvear er Without danger of buckling This I ac complisli by, the useofflevermeehanisni which when the limb is straight will' react under load'to resistjbuek lin k Another olijeet is the ,profvision'of an improved ankle jointwvh ich wiltfunction to pro:

videa; natural footaotion about ardefinite'axis' and at the; sametime permit a slight" deviation from this true action to-perinit'the footto accommodate i tselif' to-shglit u'nevenness 1n the tread surface.

Another object is the provision of'improved means for coordinating theknee and ankle actionsr I v Other-objects and-advantages will appear from the followingdescript'ion of an illustrative embodiment of-the present invention.

In the drawings v Figure 1 is al longitudinal sectional vie'vvof an a rtifieial limb constructed in accordance withthe'present invention.

Fig. 2 -is atransverse sectional fview of the knee jointtaken substantially 'alongthe line 22of Figure 1.1 I I V Fi'gr3 is a transverse sectional 'view of the shank portion taken substantially along the line 33. I v p y Fig: 4*isavertical sectional view of'the ankle jointtaken substantially along the line 4%;-

The artificial limb selected for illustration includes the usual thigh portion 10; shank portion 11 and foot 12 eachcon'stiiibted and fitted to the other in manner Well known in the art. The operating connections he-f tween these parts are new, however, and will be described 'in detail.

The thigh portion is supported upon the upper en'd of'a lever 13, lnounted'intermediate its ends upon a transverse pivot pin 14, ili ed within the shank portion 11 intermediate the ends thereof. Inth'e limb shown the pivot pin 14' extends through two inwardly projecting lugs 15 Within theshank portion Whichsupport the pin and serve to retain the lever 13"\i'ithi'n a. central plane of tiie'shan'k portion. The "upper" endof the lever 13 carri es tiv'o pins 16 and 17 projecting" laterally tlierethrongh and through curved slots 12:? and 133', instinctively, formed? in ah appropriate bracket 20 fixed to and depending from tl1e'thigl1 portion 10. p

k The bracket20-shown isef invemd- U fornh. It includes a top-plate 2'1, rigidly secured to at'ransverse partition QQ' fhrIned iii'the lower portion of thefthigh 10, and two integral side plates" 23 depending therefrom. The lower ends of the side plates2'3 are preferably rigidly connected'b'y ineansof a rod 24 or the like which cooperates with the top plate 2 ii to maintain a'definite uniform spacingbeti'veenthe' plates. Each end of pin '16 ridesin the slot 1 8"fornied in'each side plate and each endof pin'li' rides in the shit it? formed in each side plate; Appropriate spacer sleeves 25' are preferably fittedfon each pin in order to properly position the lever. Theside plates are" also slotted, as at 26, to receive a transverse g'uide'pin 27, fixed within the up pere'nd ofthe sli'ank'portion, and serving to positionfaiid guide the bracket Within the shank portion.

It will benoted that theslots 18 and 19 are so'tlisposed that \viththe limb in the straight iuli-line posit'io'n the levee 18 isinclined rearn 'ardly from its supportin 'pivot pin lei, it \vill a'lso he noted thatthe slots-areso di--' r'ccted that, in order fort'he thigh portion to swingdownwardly from this upright position toward the dotted line'po'sition, the up er end of the lever mustswing forn-ard-Iy toward the dotted line position. With the limb straight and the lever inclinedr'earward-1y however a vertical load applied to the thigh portion rea'c'ts againstthelever to prevent forward swinging thereof, and the limb is thus locked against buckling under this vertical load. In this respect the lever 13 and bracket 20 function as an ordinary toggle mech anism which wnen aduisted beyond dead center position in one direction will resist buckling in the opposite direction. A knee joint constructed in this manner will permit the wearer to rest his entire weight upon the straight limb, while standing, without fear of the same buckling beneath him.

The usual slip straps 28 and 29 are preferably employed to control the knee action when walking. These are associated with the Well known shoulder harness in the customary manner. The forward strap 28 is passed over the pin 17 and fixed to the pin 16, so that when-tensioned it tends to pull pin 16 upwardly in the slot 18 to thereby bend the knee. The rear strap 29 passes over the pin 27 and beneath the pin 24-, and is fixed to the pin 16, so that tension applied thereto draws thefpin 16 toward the lower end of slot 18 to thereby straighten the knee. Thus as the limb is advanced to take a forward step the tension thereby produced in strap 29 holds the knee against bending so that the limb remains in a straight position ready to assume the weight of the wearer. Then as the limb is swung rearwardly the tension produced in strap 28 causes the knee to bend slightly, thereby swinging the shank portion upwardly and lifting the foot clear of the tread surface. This alternate tensioning or" the straps is a condition well known in the art and therefore requires no further explanation.

In the limb shown the foot 12 is connected to the shank portion 11 through a pivot pin 30 anchored at its opposite ends in appropriate spaced brackets 31 secured to the shank portion. This pin 30 is snugly titted within an eye 32 of an anchor bolt 33 fixed in the central portion of the foot. The brackets 31 bear upon appropriate resilient pads 34L, preterably of rubber, embedded in the sides o't' the foot. This connection permits the foot to swing ireely about the axis oi the pin 30. The pads 3i sustain the load imposed upon the limb and also yieldably permit slight lateral flexibility to permit the foot to aceonimodate itself to unevenness in the tread sur'tace.

Provision is preferably made for coordinating the knee and ankle actions. In the limb shown this is accomplished by extending thelever 13 downwardly and effecting an operative engagement between it and the foot. In this instance an upright yoke 35, anchored to the foot, is forked as at 36 to receive a transverse loop portion 37 formed at the lower end oi? the lever. The arrangement is such that all movements of the lver 13, re-

sulting from a bending of the knee, are

transmitted through the yoke 35 to bend the ankle.

Various changes may be made in the embodiment of the invention hereinabove described without departing from the invention as defined in the appended claims.

I claim 1. In an artificial limb the combination of thigh and shank portions, a. lever rockably mounted in one of said portions, a bracket carried by the other of said portions and having a load sustainingconnection with said lever, and a guide connection between-said bracket and said first named portion.

2. In an artificial limb the combination of a shank portion,a lever rockably supported thereby, a thigh portion rockably engaged with and forming a guide connection between said pop tions independently of said lever.

3. In an artificial limb the combination of a shank portion, an upright lever rockablysupported thereby, a thigh portion, a bracket depending from said thigh portion into said shank portion and rockably engaged with and supported by said lever, and means forming a guide connection between said portions independently of said lever.

4. In an artificial limb the combination of a thigh portion, a bracket depending therefrom, slots in said bracket, a shank portion, an upright lever rockably supported by said shank portion, and means on said lever slidably engaged in said slots to form a load sustaining connection therebetween.

5. In an artificial limb the combination of a thigh portion, a shank portion, a bracket depending from said thigh portion into said shank portion, a slot in said bracket,a guide pin fixed in said shank and engaged'in said slot, an upright lever rockably mounted withsupported by said lever, and meansin said shank portion,additional slots in said I bracket, and pins carried by said lever and slidably engaged in said slots.

6. In an artificial limb the combination of a thigh portion, a shank portion, a bracket depending from said thigh portion into said shank portion, an upright lever rockably supported in said shank portion, two slots of different curvature formed in said bracket, and two pins on said lever spaced longitudinally thereof and engaged within said slots.

7. In an artificial limb the combination of a thigh portion, a shankportion, a'braeket depending from said thigh portioninto said shank portion, a lever rockably supported in said shank portion, and a two point sliding connection between said lever and bracket.

8. In an artificial limb the'combinationfot a thigh portion, a shank portion, a lever rockable insaid shank portion, and sliding load sustaining connections between saidlever" and thigh portion operable to swing sa'id lever during angular adjustment between said thigh and shank portions. Y

9. In an artificial limb the combination of a thigh portion, a shank portion, a rockable connection between said portions including a thigh supporting lever rockably supported by said shank portion and movable with respect to both therebetween,

connection between said portions independ- 5 ently of said leve 10. In an artifi thigh and shank tions therebetwee r. cial limb the combination of portions, rockable connecn including a thigh supporting lever rockably supported in said shank portion and movable with respect to both portions during rocking action therebetween, and a foot portion rockably connected with said shank portion and actuated by said lever. In Witness whereof, I hereunto subscribe my name this 21st day of October, 1926.

KARL N EUMAN N 

